Effectiveness of C1-INH therapy in angiotensin converting enzyme inhibitor induced angioedema

Introduction

Angiotensin Converting Enzyme Inhibitors (ACEI) are a common cause of Emergency Room presentation for angioedema. Although no treatment guidelines exist, C1 esterase inhibitor concentrate (C1-INH) is used on an off label basis for management of ACEI acquired angioedema (ACEI AAE).

Objective

To evaluate the efficacy of C1-INH in management of ACEI AAE at our local centers.

Results

Nine patients, from 3 academic sites, were identified through Allergy Service consultation data and records from Diagnostic Services Manitoba, Canada from 2010–2020. The majority of the patients (n = 8/9) required endotracheal intubation prior to the initiation of C1-INH. Overall, approximately 56% of patients (n = 5/9) had resolution of angioedema ranging between 12 and 17 h, with a median time of 13.5 h, and no recurrence after the administration of C1-INH concentrate. One patient had transient symptom resolution in 14 h, however, recurrence of angioedema required re-intubation. The remainder of patients (n = 4/9), had resolution of angioedema between 22 and 72 h, with a median time of 33.75 h.

Conclusion

Our findings demonstrate continued ambivalence of the efficacy and role of C1-INH concentrate in the treatment of ACEI AAE, secondary to multiple uncontrolled confounding factors. Further research into characterizing a subgroup of intubated patients in our study that responded to C1-INH concentrate needs to be completed.

Review of icatibant use in the Winnipeg Regional Health Authority

BACKGROUND

This is a retrospective review of the Winnipeg Regional Health Authority's (WRHA) angioedema patients who were dispensed icatibant in hospital. Icatibant is a bradykinin B2 receptor antagonist indicated for Hereditary Angioedema (HAE) types I and II and is used off-label for HAE with normal C1INH (HAE-nC1INH) and ACE-inhibitor induced angioedema (ACEIIAE). The WRHA's use of icatibant is regulated by the Allergist on call. We characterized icatibant's use and the timeline from patient presentation, compared the real-world experience with the FAST-3 trial and hypothesized the factors which may affect response to icatibant.

METHODS

Background data were collected on patients. Angioedema attack-related data included administered medications, performed investigations and the timeline to endpoints such as onset of symptom relief. Data was analyzed in R with the package "survival." Time-to-event data was analyzed using the Peto-Peto Prentice method or Mann-Whitney U-test. Data was also compared with published clinical trial data using the Sign Test. Fisher's Exact Test was used to produce descriptive statistics.

RESULTS

Overall, 21 patients accounted for 23 angioedema attacks treated with icatibant. Approximately half the patients had a diagnosis of HAE-nC1IHN and half of ACEIIAE. Of those presenting with angioedema, 65% were first treated with conventional medication. Patients without a prior angioedema diagnosis were evaluated only 40-50% of the time for C4 levels or C1INH function or level. The median time from patients' arrival to the emergency department until the Allergy consultant's response was 1.77 h. Patients with HAE-nC1IHN had median times to onset of symptom relief and final clinical outcome (1.13 h, p = 0.34; 3.50 h, p = 0.11) similar to those reported in FAST-3 for HAE I/II. Patients with ACEIIAE had longer median times to onset of symptom relief (4.86 h, p = 0.01) than predicted.

CONCLUSIONS

HAE-nC1INH may be an appropriate indication for treatment with icatibant. Conversely, the results of this study do not support the use of icatibant for the treatment of ACEIIAE, concordant with a growing body of literature. Patients should be stratified into groups of more- or less-likely icatibant-responders through history and laboratory investigations in order to prevent potential delays.

Adult-onset IgE-mediated food allergy at a Winnipeg allergy clinic: a case series

BACKGROUND

It is a putatively understood phenomenon that the overall prevalence of allergic disease has been increasing in recent decades-particularly in industrialized nations. Despite this, there is a relative scarcity of data concerning the development of food-related allergic disease in the adult population. In addition, the paucity of data as it pertains to the Canadian population is particularly marked when compared to other nations. We sought to determine common culprit foods and the reactions they elicited in a series of 14 patients seen in the Winnipeg allergy and immunology clinic.

METHODS

We conducted a retrospective review of patients identified by academic allergists in Winnipeg, Manitoba as fitting criteria for adult-onset IgE-mediated food allergy from May 2018-July 2020. We included patients with IgE-mediated symptoms, including the pollen-food syndrome which developed at the age of 16 or later. We collected data regarding the food which induced the reaction, what the reaction was, and any concomitant atopic disease.

RESULTS

The most common culprit food identified was shellfish, followed by finfish, pollen-food syndrome, and wheat/flour. The most common reaction experienced was anaphylaxis, followed by food-dependent exercise-induced anaphylaxis and isolated (muco)cutaneous symptoms. With regard to concomitant atopic disease, allergic rhinitis/rhinoconjunctivitis stood out as the most prevalent.

CONCLUSIONS

Adult-onset food allergy-particularly with resultant anaphylaxis-is an important phenomenon to recognize, even when patients have previously tolerated the food in question.

Delivery of subcutaneous immunoglobulin by rapid "push" infusion for primary immunodeficiency patients in Manitoba: a retrospective review

Background

Both intravenous and subcutaneous human immune globin G (IgG) replacement (IVIG and SCIG, respectively) reduce severe infection and increase serum IgG levels in primary immune deficiency disorder (PIDD) patients who require replacement. SCIG can be administered either with the aid of an infusion pump, or by patients or caregivers themselves, using butterfly needles and a syringe (“SCIG push”). SCIG offers advantages over IVIG, including higher steady state IgG levels, improved patient quality of life indicators, and decreased cost to the healthcare system, and for these reasons, SCIG has been increasingly used in Manitoba starting in 2007. We sought to determine the effectiveness of SCIG push in our local adult PIDD population.

Methods

We conducted a retrospective chart review of all adult patients enrolled in the SCIG push program in Manitoba, Canada from its inception in November 2007 through September 2018. We included patients who were naïve to IgG replacement prior to SCIG, and those who had received IVIG immediately prior. We collected data regarding serum IgG levels, antibiotic prescriptions, hospital admissions, and adverse events during a pre-defined period prior to and following SCIG initiation. Statistical significance was determined via two-tailed t-test.

Results

62 patients met inclusion criteria, of whom 35 were on IVIG prior and 27 were IgG replacement naïve. SCIG push resulted in an increase in serum IgG levels in those naïve to IgG replacement, as well as in those who received IVIG prior. SCIG push also resulted in a statistically significant reduction in number of antibiotic prescriptions filled in the naïve subgroup, and no significant change in antibiotics filled in the IVIG prior group. 8/62 PIDD patients (12.9%) left the SCIG program during our review period for varying reasons, including side-effects.

Conclusions

In a real-life setting, in the Manitoba adult PIDD population, SCIG push is an effective method of preventing severe infections, with most patients preferring to continue this therapy once initiated.

A novel combination of an IgE mediated adult onset food allergy and a suspected mast cell activation syndrome presenting as anaphylaxis

BACKGROUND

Adult onset food allergy is a rare, but increasingly recognized phenomenon. Mast cell activation syndromes present an ongoing diagnostic and classification challenge. The combination of the two has been rarely described in the literature.

CASE PRESENTATION

We present a case of a new onset, IgE mediated food allergy in combination with a mast cell activation syndrome in an elderly patient not known to have a history of atopy. He presented to a hospital with a first presentation of anaphylaxis manifesting profound hypotension following consumption of a stew consisting of fish and shellfish. He had a persistently elevated serum tryptase and demonstrated evidence of high titre serum specific IgE to shellfish. He responded well to histaminergic blockade.

CONCLUSIONS

Given that mast cell activation syndromes pose an increased risk for recurrent, severe anaphylaxis and that secondary causes of mast cell activation syndromes are more prevalent with aging, this case highlights the importance of considering this entity when evaluating an elderly patient with a first presentation of anaphylaxis.

A retrospective comparison of false negative skin test rates in penicillin allergy, using pencilloyl-poly-lysine and minor determinants or Penicillin G, followed by open challenge

Background

A history of penicillin allergy in patients is common, but only 10–15 % are truly allergic. While the gold standard for diagnosing penicillin allergy is challenge, it is not recommended that this be done without first carrying out diagnostic skin testing. This is carried out with the major determinant benzylpenicilloyl (PPL) and the minor determinant mixture (MDM), consisting of penilloate, penicilloate and Penicillin G. However, since availability of the MDM is limited, Penicillin G alone has been used.

Methods

A retrospective chart review was carried out on patients tested for penicillin allergy in the Clinical Immunology and Allergy Clinic at the Health Sciences Centre, Winnipeg, Canada between 2005 and 2013. A total of 521 patients charts were reviewed, of whom 240 had skin testing, ImmunoCap^® for IgE to Penicillin G and V and had oral challenges with penicillin, amoxicillin or cloxacillin.

Results

17/240 (7.5 %) were skin test positive, 8 to PPL, 4 to MDM and 5 to Penicillin G. One was also positive on ImmunoCap^® testing. Three patients had negative skin tests but weakly positive ImmunoCap^®. 222 patients with negative skin tests and serological tests were challenged. Of these, 12 patients reacted to challenge. Three of the challenges were equivocal. Of the nine patients with definite positive challenges, three were tested with Penicillin G and six with MDM. Therefore the false negative rates for testing were 2.3 % with PPL and Penicillin G and 6.97 % for PPL and MDM. The difference was not significant (p = 0.0856).

Conclusions

In this group of patients with a history of penicillin allergy tested with the major determinant of benzyl penicillin and either MDM or Penicillin G, there was no difference in the rate of false negative testing, based on oral penicillin challenges. Therefore, Penicillin G can be safely used as an alternative to MDM in diagnosing penicillin allergy.

Assessment of epicutaneous testing of a monovalent Influenza A (H1N1) 2009 vaccine in egg allergic patients

BACKGROUND

H1N1 is responsible for the first influenza pandemic in 41 years. In the fall of 2009, an H1N1 vaccine became available in Canada with the hopes of reducing the overall effect of the pandemic. The purpose of this study was to assess the safety of administering 2 different doses of a monovalent split virus 2009 H1N1 vaccine in egg allergic patients.

METHODS

Patients were skin tested to the H1N1 vaccine in the outpatient paediatric and adult allergy and immunology clinics of the Health Sciences Centre and Children's Hospital of Winnipeg, Manitoba Canada. Individuals <9 years of age were administered 1.88 μg's of hem-agglutinin antigen per 0.25 ml dose and individuals ≥9 years were administered 3.75 μg's of hemagglutinin antigen per 0.5 ml dose. Upon determination of a negative skin test, the vaccine was administered with a 30 minute observation period.

RESULTS

A total of 61 patients with egg allergy (history of an allergic reaction to egg with either positive skin test &/or specific IgE to egg >0.35 Ku/L) were referred to our allergy clinics for skin testing to the H1N1 vaccine. 2 patients were excluded, one did not have a skin prick test to the H1N1 vaccine (only vaccine administration) and the other passed an egg challenge during the study period. Ages ranged from 1 to 27 years (mean 5.6 years). There were 41(69.5%) males and 18(30.5%) females. All but one patient with a history of egg allergy, positive skin test to egg and/or elevated specific IgE level to egg had negative skin tests to the H1N1 vaccine. The 58 patients with negative skin testing to the H1N1 vaccine were administered the vaccine and observed for 30 minutes post vaccination with no adverse results. The patient with the positive skin test to the H1N1 vaccine was also administered the vaccine intramuscularly with no adverse results.

CONCLUSIONS

Despite concern regarding possible anaphylaxis to the H1N1 vaccine in egg allergic patients, in our case series 1/59(1.7%) patients with sensitization to egg were also sensitized to the H1N1 vaccine. Administration of the H1N1 vaccine in egg allergic patients with negative H1N1 skin tests and observation is safe. Administering the vaccine in a 1 or 2 dose protocol without skin testing is a reasonable alternative as per the CSACI guidelines.

Hereditary angiodema: a current state-of-the-art review, VII: Canadian Hungarian 2007 International Consensus Algorithm for the Diagnosis, Therapy, and Management of Hereditary Angioedema

BACKGROUND

We published the Canadian 2003 International Consensus Algorithm for the Diagnosis, Therapy, and Management of Hereditary Angioedema (HAE; C1 inhibitor [C1-INH] deficiency) in 2004.

OBJECTIVE

To ensure that this consensus remains current.

METHODS

In collaboration with the Canadian Network of Rare Blood Disorder Organizations, we held the second Canadian Consensus discussion with our international colleagues in Toronto, Ontario, on February 3, 2006, and reviewed its content at the Fifth C1 Inhibitor Deficiency Workshop in Budapest on June 2, 2007. Papers were presented by international investigators, and this consensus algorithm approach resulted.

RESULTS

This consensus algorithm outlines the approach recommended for the diagnosis, therapy, and management of HAE, which was agreed on by the authors of this report. This document is only a consensus algorithm approach and continues to require validation. As such, participants agreed to make this a living 2007 algorithm, a work in progress, and to review its content at future international HAE meetings.

CONCLUSIONS

There is a paucity of double-blind, placebo-controlled trials on the treatment of HAE, making levels of evidence to support the algorithm less than optimal. Controlled trials currently under way will provide further insight into the management of HAE. As with our Canadian 2003 Consensus, this 2007 International Consensus Algorithm for the Diagnosis, Therapy, and Management of HAE was formed through the meeting and agreement of patient care professionals along with patient group representatives and individual patients.